99 KX 250 cuts out intermittently

[tkiger]

I have a 99 KX 250 that starts to cut out sporadically after about 5 minutes of riding. It sputters at both low and high rpms, and once in a while it will even die and it takes a few minutes to get it started again. Sometimes it will accelerate strongly through all the gears, but it will lose it's strength again at any moment. When it is started cold, it will usually run fine for about 5 minutes. The engine does not feel any hotter than normal.

I've changed out the plug, checked the air filter and put brand new gas in it, to no avail. Any thoughts before I start pulling it apart? I really don't know what I'm looking for, but I figure it couldn't hurt to clean out the carb. I have not performed much maintenance on it since I bought it two years ago (besides changing the filters and fluids, of course).

Thanks,

-Travis

 

[rickyd]

Sounds like the stator is going bad..Could also be a bad kill switch.. EIther way, sounds electrical..
Rick

 

[tkiger]

Can you tell me what makes you think it would be electrical? The fact that it seems to run fine when it's cold would make me think it has something to do with air/fuel. Then again, I don't know much about fixing dirt bikes.

 

[JTurn36178]

What he means by electrical is: Something in the ignition circuit (electrical) is sporatically faulting. Such as the kill switch wire or button is grounding to the handle bar etc. Check the entire length of the wire through the mag cover. This is a common place where the insulation on the wire will crack and short out. He is also suggesting that the stator winding insulation could be going bad, causing the wires to short together and lose their ability to create enough electron flow to fire you plug. It could also be the coil. The best way is to test (either by switching out the suspect coil or plug wire or end of plug wire (the part that goes on the spark plug) or the stator the part inside the flywheel that bolts to the lower engine case, with a buddy's good one or a new one. Then see which one fixes it. I mentioned the plug end of the wire because corrosion can cause a high resistance connection in the circuit and heat increases resistance and this could be a reason why it works when it's cold and wouldn't when it gets hot. It would be the easiest fix.

Good Luck,
Jim